The present invention relates to methods and apparatus for separating individual blanks from a stack of blanks, and has particular application in the automotive body fabrication field.
Body parts for certain vehicles are fabricated from several body blanks. In the automotive industry, these blanks have for the most part, been made of steel thus producing steel bodied automobiles, trucks, etc. More recently there has been a trend in the automotive industry in particular, to move towards the use of aluminium to produce partial or entire aluminium bodied vehicles.
In the body fabricating process, blanks are typically delivered to an input end of an assembly line process in a stacked arrangement. One at a time, these blanks are then transferred from the stack and fed into the fabrication system on a continuous basis. To feed the blanks into the system it is necessary to separate one blank from the stack so that a single blank at a time can be fed serially into the assembly line system. However, in the blank fabrication process itself, a lubricating fluid is used when making the blanks to assist in preventing damage and prevent oxidation as one blank is placed on top of another to form a stack of blanks. Unfortunately, by the time the stack of blanks has reached the body fabrication facility and is ready to be utilized in the body manufacturing process, the lubricating film has often thickened or hardened and may tend to act as a bonding agent between adjacent blanks stacked on top of one another. This makes the task of separating individual blanks from the stack quite a difficult operation.
However, the high speed destacking of blanks is a critical aspect of the fabrication process if one wants to ensure continuous, productive operation of the body fabrication system.
In an example of a body fabrication process, the blanks are typically stored in a stack on a pallet and moved to a separation station by a forklift. At this station the pallet is placed on a lift device, such as a lift table, which then elevates the stack to present the top blank to a blank separation apparatus or destacker. A known separation device for steel blanks includes several components including an overhead, movable pick up device that employs vacuum suction cups which can be positioned above the stack. The suction cups can be lowered into engagement with and attach themselves to the upward facing surface of the top blank on the stack. For steel blanks, it is known to employ magnets which are disposed at the edges of at least the top two steel of the stack. The magnets, which may be permanent magnets or electromagnets, can create a magnetic charge in at least the top two steel blanks, causing these top two blanks in the stack to repel each other. The result is that there is fanning or separation of the edges of the sheets. This fanning permits any seal that has been created between the top two blanks to be broken, and it is possible for the overhead mounted pick-up device with suction cups to then pick up the top most blank and separate it from the rest of the stack of blanks. The blanks are then moved by the pick-up apparatus to a drop off position where the vacuum at the suction cups is removed. There the blank is dropped onto a conveyor which moves the individual blank to various body fabricating stations for processing.
The separation of individual blanks from the stack of blanks continues as each blank in turn is indexed into the proper position relative to the magnets until the stack is exhausted of blanks. This sort of blank separation apparatus is quite flexible for the handling of different shaped and sized blanks, multiple blanks and patterned blanks, as well as either tailor welded or laser welded blanks. Furthermore, this type of separation apparatus is capable of handling blanks of different thicknesses. However, this type of separation device, because it uses magnetic forces to assist in separating the blanks from each other, does not work with aluminium, or other materials which can not be charged magnetically.
Accordingly, it is particularly desirable to have an apparatus which can assist in separating blanks from a stack of blanks which can not be charged magnetically, for example a sack of aluminum blanks. At the same the it is desirable to have automated separation system which minimizes he number of reject blanks (ie. Blanks which can not be separated from the stack, as this help minimize costs.
An apparatus for separating a first blank from a stack of blanks comprising said first blank and a second blank positioned beneath of said first blank, said apparatus comprising: a nozzle assembly having at least one pressure nozzle; a source of pressurized fluid in communication with said at least one pressure nozzle to provide pressurized fluid to said nozzle; a pick up assembly having a pick up apparatus mounted thereon and operable to pick up said first blank when located proximate thereto; said nozzle assembly and said stack of blanks being movable relative to each other to bring said at least one pressure nozzle into a position proximate said stack of blanks and oriented so that said at least one nozzle can direct pressurized fluid at said side edge of said first blank; said pick up apparatus operable to be positioned proximate said first blank to pick up said first blank, said source of pressurized fluid supplying said at least one nozzle with pressurized fluid directed at the side edge of said first blank to assist said pick up apparatus in separating said first blank from said second blank; whereby said first blank can be separated from said second blank by said pick up apparatus assisted by pressurized fluid from said at least one nozzle.
An apparatus for separating a first blank from a stack of blanks comprising said first blank and a second blank positioned beneath said first blank, wherein said first and second blanks each have at least one edge, said edge of said first blank and said edge of said second blank being substantially aligned one above the other, said apparatus comprising: a pick up assembly having a pick up apparatus mounted thereon and operable to pick up said first blank when located proximate thereto, and said pick up apparatus further comprising an edge lifting device, operable to lift said edge of said first blank from said edge of said second blank; and said pick up apparatus operable to be positioned proximate said first blank to pick up said first blank once said edge lifting device has lifted said edge of said first blank from said edge of said second blank; whereby said first blank can be separated from said second blank by said pick up apparatus assisted by said edge lifting device.
A method of separating a blank from a stack of blanks comprising at least a first blank and a second blank positioned beneath said first blank using a pick up assembly, said method comprising the steps of: applying a force with said pick up assembly to said first blank so as to lift said first blank away from said second blank; forcing a fluid against a side edge of said first blank to assist said pick up assembly; and removing said first blank from said stack of blank
A method of separating at least one blank from a stack of blanks comprising at least a first blank on top of a second blank comprising the steps of: applying a first force at an edge of said first blank in a direction away from said stack of blanks; applying a second force a distance from said edge of said first blank; and separating said first blank from said stack of blanks.
An apparatus for separating at least one blank from a stack of blanks comprising a first blank and a second blank positioned beneath said first blank, said apparatus comprising: a frame; an air nozzle assembly having at least one air pressure nozzle able to discharge air at pressures higher than ambient mounted to said frame; a first pickup apparats movably mounted to said frame operable to apply a first force at the edge of said first blank so as to separate said first blank from said second blank; a second pickup apparatus movably mounted to said frame operable to apply a second force to the interior of said first blank so as to assist said first pick up apparatus in separating said first blank from said second blank; said first and second pickup apparatuses positioned proximate the upward facing surface of said first blank and movable from a first position to engage said first blank of said stack and a second position a distance from the upper surface of said stack of blanks; and said air nozzle assembly positioned proximate to the edges of said blanks of said stack of blanks and said air nozzle assembly and said stack of blanks being movable relative to each other and said air nozzle assembly positioned to assist in the separation of said first blank from said blank by directing pressurized air at the edge of said first blank whereby said edge of said first blank is separated from said second blank prior to said interior of said first blank being separated from the interior of said second blank.
An apparatus for separating a first blank from a stack of blanks comprising said first blank and a second blank positioned beneath of said first blank, said apparatus comprising: means to direct a pressurized fluid; a source of pressurized fluid in communication with said means to direct said pressurized fluid; a pick up means for picking up said first blank when said first blank is located proximate thereto; said means to direct said pressurized fluid positioned to direct pressurized fluid at said side edges of said first blank and said second blank; said pick up means operable to be positioned proximate said first blank to pick up said first blank, said source of pressurized fluid supplying said means to direct pressurized fluid with pressurized fluid which is directed at the side edges of said first and second blanks to assist said pick up apparatus in separating said first blank from said second blank; whereby said first blank can be separated from said second blank by said pick up means assisted by pressurized fluid emitted from said means for directing pressurized fluid.
An apparatus for separating a first blank from a stack of blanks comprising said first blank and a second blank positioned beneath said first blank, wherein said first and second blanks each have at least one edge, said edge of said first blank and said edge of said second blank being substantially aligned one above the other, said apparatus comprising: a pick up means for picking up said first blank when said first blank is located proximate thereto, and said pick up means further comprising an edge lifting means, operable to lift said edge of said first blank from said edge of said second blank; said pick up means operable to be positioned proximate said first blank to pick up said first blank once said edge lifting device has lifted said edge of said first blank from said edge of said second blank; whereby said first blank can be separated from said second blank by said pick up apparatus assisted by said edge lifting device.
Aspects of the invention are adapted to direct pressurized fluid (e.g., air) at the edges of a first and a second blank so as to separate the first blank from the second blank. The pressurized air may be directed from two separate nozzles, each nozzle directing pressurized fluid at differing pressures. A first nozzle, which may be oriented to direct pressurized fluid in a downward direction, may direct pressurzed fluid at a relatively high pressure (e.g., about 60-160 p.s.i.) while a second nozzle, which may be oriented to direct pressurized fluid in an upward direction, may direct fluid at a relatively low pressure (e.g., about 40-120 p.s.i.). The first and second nozzle may operate for different periods of time. The time of operation of the first nozzle may overlap with the time of operation of the second nozzle. The first nozzle may be adapted to assist in the initial separation of the first blank form the second blank. The second nozzle may be adapted to further separate the first blank from the second blank.